A semiconductor device such as an LSI is manufactured by undergoing various processes including etching, CVD (chemical vapor deposition), and the like. A semiconductor manufacturing apparatus configured to perform these processes includes a substrate pedestal located inside a chamber. A semiconductor substrate is heated to a given temperature by the substrate pedestal and is then subjected to various processes in this state.
It is known that particles may be generated by rubbing between the substrate pedestal and the semiconductor substrate in the course of the processes because there is a difference in the thermal expansion coefficient between the substrate pedestal and the semiconductor substrate. Such particles lead to reduction in yield of semiconductor devices and it is therefore preferable to suppress generation of the particles in order to improve the yield.
There is proposed a method applicable to a case of using an electrostatic chuck as the substrate pedestal. The method intends to suppress generation of particles by using a pulse voltage as a voltage for generating an electrostatic attractive force after a semiconductor substrate is mounted on the electrostatic chuck.
According to this method, the semiconductor substrate is allowed to slide on the electrostatic chuck because the electrostatic attractive force disappears in a period when the voltage is set to 0 V. Thus, a stress attributed to a difference in the thermal expansion coefficient between the semiconductor substrate and the electrostatic chuck is relaxed and the number of particles is supposed to be reduced as a consequence.
However, if the electrostatic attractive force is caused to disappear frequently as described above, then it takes a long time for starting a process after the semiconductor substrate is mounted on the electrostatic chuck because generation of a sufficient electrostatic attractive force for fixing the semiconductor substrate uses time.
The techniques related to this application are disclosed in Japanese Laid-open Patent Publications No. 2000-21964, No. 2000-260855, No. 2005-38947, and No. 05-304196.